Talk by Stuart Hammeroff, University of Arizona, Tucson. Given to the Redwood Center for Theoretical Neuroscience at UC Berkeley.
Abstract: Do mental states derive entirely from brain neuronal membrane activities? Neuronal interiors are organized by microtubules (‘MTs’), protein polymers proposed to encode memory, process information and support consciousness. Using nanotechnology, Bandyopadhyay’s group at MIT has shown coherent vibrations (megahertz to 10 kilohertz) from microtubule bundles inside active neurons, vibrations (electric field potentials ~40 to 50 mV) able to influence membrane potentials. This suggests EEG rhythms are ‘beat’ frequencies of megahertz vibrations in microtubules inside neurons (Hameroff and Penrose, 2014), and that consciousness and cognition involve vibrational patterns resonating across scales in the brain, more like music than computation. MT megahertz may be a useful therapeutic target for ‘tuning’ mood and mental states. Among noninvasive transcranial brain stimulation techniques (TMS, TDcS), transcranial ultrasound (TUS) is megahertz mechanical vibrations. Applied at the scalp, low intensity, sub-thermal ultrasound (TUS) safely reaches the brain. In human studies, brief (15 to 30 seconds) TUS at 0.5, 2 and 8 megahertz to frontal-temporal cortex results in 40 minutes or longer of reported mood improvement, and focused TUS enhances sensory discrimination (Legon et al, 2014). In vitro, ultrasound promotes growth of neurite outgrowth in embryonic neurons (Raman), and stabilizes microtubules against disassembly (Gupta). (In Alzheimer’s disease, MTs disassemble and release tau.) These findings suggest ‘tuning the brain’ with TUS should be a safe, effective and inexpensive treatment for Alzheimer’s, traumatic brain injury, depression, anxiety, PTSD and other disorders. References: Hameroff S, Penrose R (2014) Phys Life Rev http://www.sciencedirect.com/science/article/pii/S1571064513001188; Sahu et al (2013) Biosens Bioelectron 47:141–8; Sahu et al (2013) Appl Phys Lett 102:123701; Legon et al (2014) Nature Neuroscience 17: 322–329